First-principles study of ternary graphite compounds cointercalated with alkali atoms (Li, Na,...
Ri, Gum-Chol; Yu, Chol-Jun; Kim, Jin-Song; Hong, Song-Nam; Jong, Un-Gi; Ri, Mun-Hyok
2016-08-30 00:00:00
First-principles calculations were carried out to investigate the structural, energetic, and electronic properties of ternary graphite compounds cointercalated with alkali atoms (AM = Li, Na, and K) and normal alkylamine molecules (nCx; x = 1, 2, 3, 4), denoted as AM-nCx-GICs. From the optimization of the orthorhombic unit cells for the crystalline compounds, it was found that, with the increase in the atomic number of alkali atoms, the layer separations decrease in contrast to AM-GICs, while the bond lengths between alkali atoms and graphene layer, and nitrogen atom of alkylamine increase. The calculated formation energies and interlayer binding energies of AM-nC3-GICs indicate that the compounds is increasingly stabilized from Li to K, and the energy barriers for migration of alkali atoms suggest that alkali cation with larger ionic radius diffuses more smoothly in graphite, being similar to AM-GICs. Through the analysis of electronic properties, it was established that more extent of electronic charge is transferred from more electropositive alkali atom to the carbon ring of graphene layer, and the hybridization of valence electron orbitals between alkylamine molecules and graphene layer is occurred.
http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.pngJournal of Power SourcesElsevierhttp://www.deepdyve.com/lp/elsevier/first-principles-study-of-ternary-graphite-compounds-cointercalated-naESh8j9MJ

Abstract

First-principles calculations were carried out to investigate the structural, energetic, and electronic properties of ternary graphite compounds cointercalated with alkali atoms (AM = Li, Na, and K) and normal alkylamine molecules (nCx; x = 1, 2, 3, 4), denoted as AM-nCx-GICs. From the optimization of the orthorhombic unit cells for the crystalline compounds, it was found that, with the increase in the atomic number of alkali atoms, the layer separations decrease in contrast to AM-GICs, while the bond lengths between alkali atoms and graphene layer, and nitrogen atom of alkylamine increase. The calculated formation energies and interlayer binding energies of AM-nC3-GICs indicate that the compounds is increasingly stabilized from Li to K, and the energy barriers for migration of alkali atoms suggest that alkali cation with larger ionic radius diffuses more smoothly in graphite, being similar to AM-GICs. Through the analysis of electronic properties, it was established that more extent of electronic charge is transferred from more electropositive alkali atom to the carbon ring of graphene layer, and the hybridization of valence electron orbitals between alkylamine molecules and graphene layer is occurred.

Journal

Journal of Power Sources
– Elsevier

Published: Aug 30, 2016

Recommended Articles

Loading...

References

Intercalation compounds of graphite

Dresselhaus, M.S.; Dresselhaus, G.

Electronic structure of superconducting graphite intercalate compounds: the role of the interlayer state